Physically entering an aircraft or similar enclosure to fight a fire or dispense a fire fighting agent in an explosive atmosphere can be very dangerous, exposing the fire fighter to an explosion or other catastrophe. The classical technique used to fight fires in a building structure involves breaking through windows with an axe or other tools, breaking down or chopping through a door, or chopping through a wall or roof. This method has proven to be unsatisfactory in many instances. When windows are broken there is a danger of injury from glass cuts. When the fire inside the building is located close to the wall or door being penetrated, there is also a danger from hot gases and flames, or an explosive action when the building is penetrated. In addition, the use of axes or other penetrating tools is time-consuming and requires considerable effort, allowing the fire to continue burning and spread while the wall is being penetrated.
As a result of the above problems, various devices have been developed for more rapidly penetrating a walled enclosure and introducing a fire fighting agent into the interior. In U.S. Pat. No. 4,676,319 to Cuthbertson, a fire fighting tool is disclosed in which a penetrating means such as a drill bit is attached to one end of a rotatable drive shaft. The shaft extends axially inside a barrel, which also serves as a conduit for a fire fighting agent. The shaft is rotated by a motor, allowing the operator to drill a hole in an enclosure and insert the end of the barrel through the hole. A fire fighting agent is dispensed into the enclosure through the barrel. The Cutherbertson device uses a portable pressurized air bottle to power the tool. This severely limits the number of times that the Cuthbertson device can be used without the need to change air bottles.
In U.S. Pat. No. 4,271,909 to Chatfield, Jr. et al., a modular fire fighting tool is disclosed in which a cylindrical barrel with a drill bit or other penetrating tool at its front end extends forward from a turbine. The turbine is driven by water or other fire extinguishing liquid, and rotates the drill bit to cut a hole in the building wall. One drawback of such prior art devices is that the fire extinguishing liquid used to drive the turbine must be collected for later disposal. Such devices are also limited because dry chemical fire retardants cannot be used to drive the turbine. The barrel is then inserted into the interior of the building, and a valve is operated which allows water to flow down the barrel and out through outlet openings located behind the bit to extinguish the fire.
In U.S. Pat. No. 3,865,194 to Chatfield, Jr. another hydraulically operated fire extinguishing drill is disclosed. After a hole has been cut in the enclosure wall and the barrel inserted, a valve is operated to permit water to issue from the end of the tool and extinguish the flame.
U.S. Pat. No. 2,251,175 to Tappe is somewhat similar in concept to the '909 patent above, in that it uses a hydraulically operated circular saw to cut a hole in a vessel, with a valve controlling the flow of water out of the barrel once the hole has been cut. The tool is mounted on an extension carried by a mobile support frame.
Another penetrator/barrel arrangement is disclosed in U.S. Pat. No. 4,147,216 to Schnepfe, Jr., et al. In this device, which is particularly designed for aircraft fires, a cartridge is fired to drive the cutter through the aircraft skin. The barrel is then moved through the opening and a fire fighting agent is dispensed into the interior of the aircraft.
Another device designed for fighting aircraft files is disclosed in U.S. Pat. No. 2,857,005 to Medlock. In this patent a penetration tool is carried at the end of an extension arm mounted on a truck. The tool punches through the aircraft shell by the forward motion of the truck, which then backs away to leave an outlet in place through which a fire fighting agent can be sprayed into the interior of the aircraft.
The foregoing devices represent improvements in the fire fighting art, in that they permit a more rapid penetration of an aircraft or other enclosure to fight a fire inside. However, they do not solve all of the potential problems. Tools which comprise both a penetration device and a fluid passageway sacrifice much of the passageway by integrating the two features. For example, in U.S. Pat. No. 4,676,319 to Cuthbertson, the shaft by which the motor drives the drilling bit runs through the fluid passageway. This approach greatly reduces the maximum fluid flow and increases the time required to extinguish a fire.
Prior tools also fail to allow for rapid replacement of drilling bits or fluid delivery devices, such as barrels. The ability to rapidly change a drill bit or to change the diameter or length of the barrel can be critical if a part breaks or if a different part will provide better performance. Modern advances in military aircraft materials have resulted in the use of titanium for aircraft hulls. Modern firefighting tools must be capable of rapidly penetrating such titanium skins. Prior art tools do not prove that capability.
Further, drilling tools are subject to significant torque when drilling into an enclosure. The present invention is capable of penetrating the titanium skin of a modem aircraft when only 150 pounds of force is applied against the tool to drive it through the titanium skin. This torque can make the tool difficult to control during the drilling process. Additionally, a considerable back pressure is developed when the tool is inserted into a craft and begins to dispense a fire fighting fluid. This pressure can make it difficult to control the tool, and may even force the tool back out of the craft. However, tools which attempt to overcome the back pressure are difficult to remove when the fire fighting operation has concluded. In addition, some of the prior devices are quite cumbersome and difficult to manually manipulate.